The present invention relates to a LCD (Liquid Crystal Display), more particularly, to a driving circuit and driving method for a LCD.
LCDs have many pixels arranged in rows and columns in their screen. Each pixel has its own electrode, i.e. pixel electrode, for applying a voltage to a liquid crystal material in that pixel. By selecting a row of pixels, the voltages are applied to the pixel electrodes in the selected row through column signal lines. Selecting all the rows sequentially, all the pixel electrodes in the screen are supplied with their own voltages. Through these voltages, the liquid crystal material in each pixel is driven and changes its orientation, thereby the amount of light passing through each pixel is controlled so that an image is displayed on the screen.
Meanwhile, it should be noted that LCDs typically have a common electrode which is commonly owned by all pixels, and to be precise, the voltage difference between the pixel electrode and the common electrode is applied to the liquid crystal material in the pixel to control the amount of passing light.
The time required for selecting all rows, i.e. all pixels in the screen, is referred to as “One field period”, and a voltage applied to the liquid crystal material in each pixel is refreshed once in the “one field period. Of course in a case there is no need to change the displayed image in a pixel, the same voltage is again applied to that pixel.
Though a LCDs, which are lightweight, lower power consumption and display exquisite images, are used widely replacing the conventional CRT displays, there is a shortcoming of lower displaying quality for moving images.
As mentioned above, LCDs can display images by controlling the amount of passing lights through the orientations of liquid crystal material. Thus, when an image with motion is displayed, i.e. displayed image must be changed, the orientation of liquid crystal material must be changed by changing voltages applied to them. However, it requires relatively long time for a liquid crystal material in certain orientation to be changed into another orientation according to the newly applied voltage. Therefore, in case of displaying object which moves at high-speed, there is a problem which causes afterimage and blurred image since the liquid crystal material can not reach the desired orientation during the “one field period”.